Among those numbers are influential first-team regulars Marcus Harness, Louis Thompson and Michael Jacobs as well as Player of the Season Sean Raggett.
Danny Cowley revealed the Blues are yet to finalise talks with any of his out-of-contract contingent over new deals – opening up the possibility of them leaving for free come June.
But how does the Fratton Park outfit’s numbers of potential free agents compare to those across the rest of League One?
We’ve taken a look at the sides with the most players out-of-contract in the summer and who could have the biggest rebuilding job ahead.
Here’s what we found.
1. Oxford United - 2
Out-of-contract players: Yanic Wildschut, Djavan Anderson. Photo: Richard Heathcote
2. Peterborough - 3
Out-of-contract players: Nathan Thompson, Joe Ward, Emmanuel Fernandez. Photo: Catherine Ivill
3. Fleetwood - 3
Out-of-contract players: Daniel Batty, Darnell Johnson, Harrison Holgate. Photo: Pete Norton
4. Forest Green - 5
Out-of-contract players: Ben Stevenson, Udoka Godwin-Malife, Dylan McGeouch, Baily Cargill, Lewis Thomas. Photo: Pete Norton